Vayne and Zenos do have a number of similarities.

-Son of the current Emperor
-Chosen to rule a conquered territory
-Worked with a scientist deemed mad
-Obtained an artificial copy of a normally divine gift
-Took on the form of a dragon for the final battle

Their personalities couldn't be more different, ruthlessness aside, but Zenos definitely fits the bill.

Still not sure when we slaughtered Garleans not in self-defense or without need. We let anyone who stands down live... and more often than not they attack us without mercy. So...